-LRB- CNN -RRB- -- Thousands on Saturday fled the area in southwestern Ivory Coast where attacks left seven U.N. peacekeepers and eight civilians dead , according to a U.N. official .

One attack occurred late Thursday and into Friday near Para Village , not far from the west-central African nation 's border with Liberia , according to the United Nations .

Humanitarian organizations reported Saturday they were expecting about 4,000 people in Tai , said Remi Dourlot , a spokesman for the U.N. Office for the Coordination of Humanitarian Affairs . Several hundred had arrived by midday Saturday in the town , which is on the edge of Tai National Park .

Another 35 families crossed the Ivory Coast 's southwest border into U.N. refugee camps in Liberia , and humanitarian groups said hundreds of others had been pushed south by the violence , according to Dourlot .

The movement comes after blue-helmeted peacekeepers -- who were in the area because of threats against civilians -- came under attack , the United Nations said in a statement .

Besides the U.N. peacekeepers , humanitarian groups reported eight civilians died in violence , said Dourlot .

U.N. Secretary-General Ban Ki-moon on Friday called on the government of Ivory Coast `` to do its utmost to identify the perpetrators and hold them accountable . '' He added that he understood other peacekeepers remained in danger .

`` Even tonight , after the attack , more than 40 peacekeepers remain with the villagers in this remote region to protect them from this armed group , '' Ban said .

U.N. Operation in Cote d'Ivoire and Ivory Coast troops have increased their presence in the area , Dourlot said Saturday . Members of the U.N. humanitarian affairs office have deployed to Tai to coordinate relief efforts there with local authorities .

Clinton urges Ivory Coast dialogue

A spokeswoman for the U.N. mission in Ivory Coast said Friday 's incident was the first attack on peacekeepers since they entered the country in 2004 .

Sylvie van den Wildenberg , in a telephone interview from her office in Abidjan , said the remaining forces were continuing to protect area residents , `` who are living in a very difficult terrain -- their villages scattered . ''

Van den Wildenberg said it was not clear who was responsible for the attack , which occurred mid-afternoon . `` This is an area where you have so many different types of armed people , '' she said . `` People have different aims and different reasons to carry arms and to perpetrate attack . So this is a very complex environment . We ca n't extrapolate . We just ca n't fingerpoint any group . ''

The peacekeepers were on a reconnaissance patrol because U.N. officials had heard rumors several days earlier of armed men in the area threatening to attack a village , she said .

U.N. peacekeepers remained in Ivory Coast after the 2010 presidential election , when the country was thrown into crisis after incumbent President Laurent Gbagbo refused to acknowledge defeat to former Prime Minister Alassane Ouattara . The latter was sworn in on May 21 . Gbagbo is in custody at the Hague , accused of crimes against humanity during post-election violence that killed thousands .

According to the United Nations , its peacekeeping force in Ivory Coast as of April 30 included nearly 11,000 uniformed personnel , as well as several hundred international civilian personnel , local staff and volunteers . They provide technical , logistical and security support to the government .

CNN 's Christabelle Fombu and Tom Watkins contributed to this report .

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Humanitarian groups expect 4,000 refugees in one camp , a U.N. official says

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Others have fled across the border to U.N. camps in Liberia , he says

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This follows attacks that killed 7 U.N. peacekeepers and 8 civilians